That's not true more than just the s and z series can hook up to a monitor I literally have two different tablets from Samsung that do it all the time also the a series can and a bunch of others. Maybe you're talking about wireless dex? In that case though you're still wrong because both of my tablets might Galaxy tabs support wireless dex so it's not just z and s line it's pretty much any newer phone from Samsung will have Miracast at the minimum and if you have a higher end model then you can utilize Samsung Dex. All you need to do is get an HDMI to USBC adapter and plug one end into the HDMI cord that's in your TV and the other end of it will go inside the bottom port of your phone and you'll either get a pop-up option for mirroring your display or a multiple option menu where you can choose dex or Miracast.
I think I misunderstood the original post, should be as simple as connecting a video cable (and make sure the monitor is plugged in). If that doesn't work check display settings for multiple displays.
